Issue regarding the co-ownership of currently dwelling flat.

I am a resident of Mumbai. The flat that I am living in right now was bought 3 years back. It's in the name of my maternal aunt and me, my maternal aunt's name being the first, and mine second, in the sale deed. The percentage of shares owned by my aunt or me is not mentioned anywhere in the sale deed. My aunt has entirely paid for the flat, and is currently paying the maintenance and electricity bills. I am paying all the other bills and the household expenses. Both my aunt and I live in this flat. We are having very cordial relations among us. Now we have found from some reliable sources that she is making a will in which: 1. She intends to declare that as only she has paid for the flat, she is the absolute owner of the flat 2. She intends to divide the flat among my father and his 2 brothers equally after her death. Please let us know that, if things proceed as they are going on now, how would the situation be after her death? How much does my father actually own in the flat? How would her will be executed (the part in the will pertaining to this flat)? Any other comments/advice would also be highly appreciated.